Apparatus for supplying cooling water to the cooling channels of the rotors of electrical machines

ABSTRACT

An apparatus for supplying cooling water to the cooling channels of an electrical machine rotor having a rotor shaft has an inlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient and an outlet chamber communicating with the rotor channels for receiving the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels. The outlet chamber surrounds the rotor shaft in liquidtight relation to the ambient. A primary circulation path for conveying the cooling water connects between the outlet chamber and the inlet chamber for conducting the cooling water between these chambers. A pump is provided for supplying the cooling water to the inlet chamber under pressure and for urging the same through the primary conveying path. A leakage water chamber is situated next to the outlet chamber in a direction toward the ambient and has a contactless seal disposed with respect to the shaft where the leakage chamber adjoins the ambient and a second contact seal where the leakage chamber adjoins the outlet chamber. The leakage chamber serves to collect cooling water which leaks through from the second seal during normal operation, the cooling water being mixed with air leaking into the leakage chamber from the ambient. The pump communicates with the leakage chamber for drawing the leakage cooling water therefrom. A source of hydrogen gas is connected to the cooling water conveying path for saturating the cooling water conveyed therein with hydrogen. An oxygen removal device receives the leakage water mixed with air and is connected between the leakage water chamber and the primary conveying path.

United States atent 91 Pluschke [54] APPARATUS FOR SUPPLYllNG COOLING WATER TO THE COOLING CHANNELS OF THE ROTORS 01F ELECTRICAL MACEHNES [75] Inventor: Manfred Plusclhke, Velbert, Germany [73] Assignee: Kraftwerk Union Aktiengesellschaft,

Mulheim Ruhr, Germany [22] Filed: April 2, 1971 [21] Appl.No.: 130,712

[30] Foreign Application Priority Data April 4, 1970 Germany P 20 16 169.7

[52] US. Cl. ..310/53, 310/61, 310/63 [51] Int. Cl. ..l1-102k 9/00 [58] Field oiSearch ..310/52,53,54,55,56,58, 310/61, 62, 63, 64

[56] References Cited UNITED STATES PATENTS Primary ExaminerR. Skudy AttorneyCurt M. Avery, Arthur E. Wilfond, Herbert LfLe rEeTa rTd fianielTTicle 1 Jan. 16, 1973 I37] AESTRACT An apparatus for supplying cooling water to the cooling channels of an electrical machine rotor having a rotor shaft has an inlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient and an outlet chamber communicating with the rotor channels for receiving the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels. The outlet chamber surrounds the rotor shaft in liquid-tight relation to the ambient' A primary circulation path for conveying the cooling water connects between the outlet chamber and the inlet chamber for conducting the cooling water between these chambers. A pump is provided for supplying the cooling water to the inlet chamber under pressure and for urging the same through the primary conveying path. A leakage water chamber is situated next to the outlet chamber in a direction toward the ambient and has a contactless seal disposed with respect to the shaft where the leakage chamber adjoins the ambient and a second contact seal where the leakage chamber adjoins the outlet chamber. The leakage chamber serves to collect cooling water which leaks through from the second seal during normal operation, the cooling water being mixed with air leaking into the leakage chamber from the ambient. The pump communicates with the leakage chamber for drawing the leakage cooling water therefrom. A

source of hydrogen gas is connected to the cooling water conveying path for saturating the cooling water conveyed therein with hydrogen. An oxygen removal device receives the leakage water mixed with air and is connected between the leakage water chamber and the primary conveying path.

22 Claims, 7 Drawing Figures PATENTEDJAN ISIHYS 3.711 731 SHEET 1 [IF 4 APPARATUS FOR SUPPLYING COOLING WATER TO THE COOLING CHANNELS OF THE ROTORS OF ELECTRICAL MACHINES My invention relates to an apparatus for supplying the cooling channels of rotors of electrical machines with cooling water and is preferably applicable to turbogenerators having direct water cooled rotor windings. The apparatus of the invention includes an inlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient. The cooling water is directed from the inlet chamber under pressure into the cooling channels. Also included is an outlet chamber which communicates with the rotor channels for receiving and conveying away the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels. A primary conveying means connects between the inlet and outlet chambers wherein the cooling water is prepared and directed back from the outlet chamber to the inlet chamber and there is at least one cool water pump for pumping the cooling water in the conveying means or circulation path as well as a water preparation and cooling apparatus in the outer circulation path.

It is known from US. Pat. No. 2,970,232 to direct the cooling water exiting from the rotor cooling channels for preparation and recooling through a cooler, an ion exchanger as well as a filter element whereby coarse contaminants are filtered out as well as anions and cations contained in the cooling water which can increase the conductivity of the cooling water in an undesired manner, for example, Cu-ions and the acid remains of carbonic acid gas I'I CO can be removed from the cooling water. With liquid cooled rotors of 3 electrical machines especially such machines having a large power rating, that is, with turbogenerators having direct water cooled rotor windings, there exists not only the problem of preparing the water and recooling it, instead, there must also be obtained an efficient and reliable sealing of the water inlet and water outlet locations with reference to'the rotor or the rotor shaft. In the above reference, ring seals are provided with respect to the rotor for supplying and directing away the cooling liquid. However, further information as to how the seals function is not given.

United States Pat. No. 2,999,951 illustrates another apparatus for liquid cooling of electric machines which relates only to the liquid cooling of the stator or stator windings; this arrangement has in its outer circulation path a cooling and/or heating exchanger, a filter, and an ion exchanger as well as a pump and oxygen removal device. Since this disclosure only relates to a stationary sealing arrangement, shaft sealing means are not discussed.

German printed Patent application No. l,l59,559 discloses a cooling means connection head for supplying and directing away the cooling medium to the liquid cooled rotors of electrical machines, especially turbogenerators wherein an axial shaft seal driven with oil or liquid is provided to seal the liquid inlet and outlet locations of the rotor against the outer atmosphere or ambient. The sealing ring of the shaft seal is pressed elastically against a shaft collar wherewith oil or the liquid acts as a lubrication means. With such contactmaking shaft seals there exists the special problem to prevent the cooling liquid or cooling circulation path from becoming contaminated with oil vapor or traces a large capacity, relatively large axial shifts can occur wherewith the shaft seal must reliably seal against the outer atmosphere in all cases. When the sealing action of the shaft seals becomes diminished, air can reach the cooling circulation path whereby oxygen of the air becomes partially dissolved in the cooling liquid and as such is especially damaging and can cause undesired corrosion on the copper or steel cooling channels or cooling tubes of the rotor.

In German Pat. publication No. 1,488,041, there is disclosed a cooling medium connection head for supplying and directing away the cooling medium to a liquid cooled rotor of electrical machines especially turbogenerators wherein a radial shaft seal is provided for sealing the cooling liquid outlet chamber against the outer atmosphere wherewith this radial shaft seal is formed substantially by a ring which surrounds the shaft with a tight tolerance. The arrangement also discloses that the shaft seal is arranged between the outlet chamber and a leakage-water chamber. From the leakage water chamber, the leakage water entering from the gap between the sealing ring and the shaft is collected and directed away. In this arrangement, the sealing gap is not arranged on a shaft collar disposed radially with respect to the shaft axis, instead, a ring gap is located between the outer periphery of the shaft and the inner periphery of the sealing ring. This shaft seal is loaded with blocking liquid or blocking gas through radial bores. A sealing during operation is possible if a small amount of cooling water is taken from the cooling liquid circulation path and directed as a blocking liquid of an inner blocking liquid circulation path of the shaft sealing in such a manner that a portion flows again to the outlet chamber or to the cooling liquid circulation path while the other portion flows into the leakage-water chamber and seals the sealing gap with respect to the outer atmosphere by means of the blocking liquid of an outer blocking liquid circulation path. In this manner, a sealing during operation is obtained. This known arrangement for shaft scaling is, however, relatively complex since its blocking water must be directed within one of the inner blocking water circulation paths and one of the outer blocking water circulation paths wherewith the pressure of the blocking water circulation paths must be determined relative to each other and must be controlled in dependence upon the pressure level of the rotor water inlet chamber and rotor water outlet chamber. In addition, in a non-operational state, no blocking water is available for the inner blocking water circulation path since the shaft pumps provided there do not pump under non-operating conditions.

It is an object of my invention to provide an apparatus for supplying cooling water to the cooling channels of rotors of electrical machines wherein the difficulties occurring during continuous operation and during non-operation with the above-mentioned shaft seals is precluded. Subsidiary to this object, it is an object of my invention to provide such a cooling apparatus for turbogenerators having direct water cooled rotor windings.

It is another object of my invention to provide a cooling apparatus for supplying cooling water to the rotors of electrical machines wherein it is not necessary to have a contact-making shaft seal and wherein the need for an inner and an outer blocking fluid circulation path with a sealing ring surrounding the shaft is precluded. Preferably, only small gap leakage water losses should occur in operation and during non-operation. Also during non-operation, the rotor winding and the entire water circulation path must remain filled so that operation can commence at any time without difficulty. In addition, the rotor water exiting from the rotor channels or entering into the latter should not contain oxygen and carbon dioxide in amounts exceeding a permissible maximum value.

The subject matter of the invention relates to an apparatus for supplying the cooling channels of rotors of electrical machines with cooling water, preferably for turbogenerators with direct water cooled rotor windings of the type mentioned in the foregoing. The apparatus includes a water preparation and return cooling assembly in the outer circulation portion through which the cooling water is filtered and freed from air inclusions and dissolved undesired contents such as oxygen, carbon dioxide and copper ions, whereby the specific conductivity is held below a highest permissible value. Also provided in the apparatus is a leakage-water chamber connected ahead of the outlet chamber in a direction toward the ambient.

According to a feature of the invention contactless shaft seals are arranged between the leakage-water chamber and the outlet chamber on the one hand as well as between the leakage-water chamber and the ambient on the other hand. Arranged with respect to the leakage-water chamber is a pump which pumps the leakage water from the same. The cooling water circulation path is connected to a gas source for saturating the cooling water with hydrogen gas. Further, a preparation container serving as an oxygen removal device is connected after the leakage water chamber in the cooling circulation path. The oxygen removal device is equipped with a palladium catalyzer which acts as a contact medium and by which the oxygen of the air-hydrogen-water mixture flowing therein from the leakage-water chamber comes into reaction with the hydrogento form water. In addition, and according to a further feature of the invention, means are provided for maintaining a hydrogen surplus relative to the oxygen content in the water flowing to the oxygen removal device and the latter has a specific capacity such that the oxygen concentration in the water circulation system remains below an upper limit value.

With reference to the contactless shaft seals it is here understood that so-called labyrinth seals are intended with sealing projections arranged with an annular gap on sealing shells at the outer periphery from the shaft and/or at the inner periphery from the shaft. The sealing projections-are arranged with respect to the mutually adjacent sealing surfaces with the formation of a radial gap. These contactless shaft seals must be so constructed that, under consideration of the axial displacements and radial movements of the shaft occurring during operation, rubbing of the sealing projections at their contacting surfaces is prevented.

Under contactless seals, so-called water-ring stuffing-box seals are also understood. These are seals with which a water-ring is moved in the rotational direction of the shaft at the angular speed of the latter by an impeller action in a ring chamber; and because of the centrifugal force, the water ring is pressed against the radially outer lying surfaces of the stationary ring chamber. Be it during operation where the shaft rotates or during non-operation, it is essential that these contactless shaft seals have a certain radial gap which permits a sealing without difficulty through which, however, on the one hand certain air quantities may reach the cooling water circulation path and, on the other hand, through which leakage water containing dissolved hydrogen can reach the leakage-water chamber from the cooling water circulation path.

According to the invention the air or oxygen quantities reaching the cooling water circulation path and hydrogen quantities from the cooling water circulation path do not have to work to a disadvantage since they can be prevented in a simple operationally reliable manner. In this connection, the oxygen removal device working with a palladium catalyzer as a contact medium plays an important role. According to the invention it'is taken into account that the water in the leakage water chamber dissolves air whose oxygen and carbon dioxide portions could by themselves lead to a corrosion in the windings. Before these dissolved gases can reach the windings and cause any damage, they are rendered not harmful. For the oxygen removal there is used in this connection the catalytic reduction of the oxygen by means of the palladium catalyzer. The chemical process thereby occasioned should not be viewed individually because it is only important that, with the aid of the palladium catalyzer, the oxygen in the watery solution with the hydrogen dissolved in larger quantities in the cooling water circulation path of the electric machine converts quantitatively directly to water. The metal palladium has the characteristic to release the molecular binding forces of the hydrogen so that the hydrogen in atomic condition with a relatively low temperature (below 20 C.) can react sufficiently fast.

In'practice, one would disperse an oxygen-hydrogen loaded anion exchanger in a palladium chloride solution; this would then be poured in a container toward a filter bed. The hydrogen saturated water dissolved oxygen is directed over the filter bed. Preferably, in this manner, a very low remainder of oxygen is obtained in the water flowing away from the oxygen removal device, the low remainder being less than 10 micrograms of oxygen per liter. However, a precondition for this result is that the required hydrogen surplus relative to the oxygen content of the water be available and that the oxygen removal device has a sufficient specific capacity or regenerating capacity. 1

The palladium contact mass does not exhaust itself and therefore does not have to be regenerated. The anion exchanger has the task to bind the dissolved carbon dioxide so that, in this manner, within an individual reaction container the surplus oxygen as well as the carbon dioxide can be removed from the cooling water.

The subject matter of the invention also relates to the application of the above-mentioned oxygen removal device equipped with a palladium catalyzer for removing the dissolved, surplus oxygen contained in the rotor cooling water circulation path of electrical machines especially with turbogenerators having direct watercooled rotor windings which are equipped with contact-making shaft seals for sealing the cooling water circulation path with respect to the outer atmosphere and as protection for the emergency condition wherein the oxygen of the air penetrates into the cooling circulation path.

The invention will now be described with reference to the drawings wherein:

FIG. I is a schematic diagram of an apparatus according to the invention for supplying and directing away cooling water to the cooling channels of the rotor of a turbogenerator;

FIG. 2 (in two parts) is a further development of the cooling apparatus illustrated in FIG. I wherein the rotor cooling circulation system has cooling branches connected thereto for the stator or the stator winding of the turbogenerator;

FIG. 3 is the cooling water connection head of FIGS. 2 and 2a enlarged to show details and is partially in section;

FIG. 3a is an enlargement of the labyrinth seal details indicated by reference character A in FIG. 3;

FIG. 3b illustrates the principles of a water-ring stuffing-box seal which can be used in addition to or in lieu of the labyrinth seal illustrated in FIG. 30 when, during operation, it is desired to have a gas-tight but yet contactless sealing of a space; and,

FIG. 4 is a section of FIG. 2 which illustrates the circuit arrangement of the feedback pump with respect to the water-circulation system of the rotor.

FIG. 1 illustrates a simple embodiment of an apparatus according to the invention for a turbogenerator l with a stator 2 and rotor 3. The stator winding of the turbogenerator is here not illustrated since its depiction is not needed for an understanding of the invention. The stator winding can preferably be a direct watercooled stator winding whose cooling channels are connected to the illustrated cooling water supply apparatus. The housing of the turbogenerator is closed in gas tight relation to the ambient, since it is usually filled with an inert gas such as hydrogen. The stator bore 2a contains the rotor 3 rotatably arranged with respect thereto and spaced therefrom by an air gap A. The rotor is suitably journaled (not shown) and with its coupling end 3a, it is coupled to a drive machine or prime mover, preferably a steam turbine which is likewise not illustrated.

Y The rotor 3 has a rotor winding 5 which is directly cooled with water and which constitutes the excitation winding of the turbogenerator. To simplify the illustration, only a single winding with both winding halves 5a, 5b, is illustrated since this is sufficient for explaining the invention. At the shaft end 3b of rotor 3 there is provided an inlet channel 6a for directing the cooling water to winding half 5a. Also provided, is an outlet channel 6b for conducting the cooling water away from winding half 5b. Arrows f indicate the flow direction of the cooling water.

The cooling water is under pressure and for directing the same to the rotor cooling channels 5a, 51), there is provided an inlet chamber Kl surrounding the shaft portion 3b of the rotor shaft in water-tight relation to the ambient. In the illustrated embodiment, a pump wheel 7a of a pump 7 draws cooling water under suction from the suction chamber K2. The water is then urged from the chamber Kll first over the conduit 1 and the external consumer constituted by a cooling device W. The cooling water is then urged through conduit portion 1 to a filter F and then through conduit portion 1 into the central bore 8a of a stationary inlet stub 8, the latter being placed tight in the outer wall 9a of the water connection head 9. This inlet stub 8 empties into the inlet channel 6a which is arranged as a central bore of the shaft portion 3b as will be illustrated in more detail in FIG. 3.

Thereafter, the cooling water is urged into the entrance channel 60 from the stationary inlet stub 8 and then into the cooling channels of the rotor winding 5. The cooling water is heated in the rotor winding 5 and is reduced in pressure by the pressure drop in the cooling channels. The water is then conducted away through the outlet channel 6b disposed concentrically about the inlet channel 6a, the channel 6b being provided with the radially positioned exit bores 60 in the outlet chamber K3.

Between the inlet chamber K1 and the outlet chamber K3 there lies the outer circulation path portions lit), M which prepare and return the water from the outlet chamber K3 to the inlet chamber Kl. A first outer primary circulation portion 10 consists of the following parts: the rotor-water outlet line 1 which connects with the outlet chamber K3 and which is provided with a check valve r1 as well as a throttle valve V6, a water storage means II serving as an expansion vessel and connected to the end of conduit 1 and having a water space lllla and a gas space lllb, and a rotor-water return conduit 1,, connecting the water storage means 11 with the suction chamber K2 and provided with throttle valve VI.

The outer primary circulation portion 10 is completed by a second outer primary circulation portion Ml which includes shaft pump 7. Shaft pump 7 forces the cooling water out from the suction chamber K2 and into the outlet chamber K1 wherewith, between the inlet stub and the inlet chamber Kll, there is connected as mentioned above, the conduit portions 1,, l and 1 with external consumers in the form of filter F and cooling device W for preparing and cooling the water.

Arranging the consumers W, F on the pressure side of the pump 7 has the advantage that at the pressure side, a reduction of the pressure level of the entering cooling water by the pressure drop of the external consumers is allowable since there are sufficient pressure reserves available at this location. For example, a reduction of the pressure level at the pressure side of pump 7 of H2 atmospheres to 10 is still a sufficient entrance pressure. At the suction side of the pump 7 there is in contrast no such reserve pressure drop available. Pressure at the suction side must be held within definite limits, that is, it must be held above a minimal pressure value so that, with respect to the water temperature, no cavitation occurs in the outlet chamber K3 and the section chamber K2.

The outlet chamber K3 is connected after a leakage water chamber K5 in a direction toward the ambient, whereby respective shaft seals W1, W2 and w3 are arranged: between the suction chamber K2 and the outlet chamber K3, between the outlet chamber K3 and the water chamber K5, and between the chamber K5 and the ambient. The leakage water passing through the shaft seal w2 travels through the chamber K5 and the opening 12 into a collection vessel 13 arranged below the water connection head 9.

An outer secondary circulation path 14 of the cooling water is connected to the collection vessel l3 via conduit 1 The secondary circulation path 14 includes the conduit 1 and a device 15 for removing oxygen, the latter being explained in more detail below. Also included in system 14 is conduit l which connects device 15 with the following: an ion exchanger A, a pump 16 and a three-way magnetic valve V3. A conduit 1 connects valve V3 via a valve channel with the collection vessel 13 and a conduit 1 connects valve V3 via a valve channel and check valve r with water storage means The ion exchanger A serially connected after the oxygen removing device 15 is preferably configured as a so-called mixed-bed filter for removing anions and cations, especially Co -ions and Cu-ions. By means of the installation of the cooler W and filter F in the primary circulation path 10, 10' as well as the installation of the oxygen removing device and ion exchanger A in the secondary circulation path 14 there is achieved in combination with the water storage means 11: a recooling and filtering of the water as well as a removal from the water of air pockets and dissolved and undesired components such as oxygen, carbon dioxide and copper ions, the water being thereby held below a highest value of the specific electrical conductivity.

' The shaft seals w2, w3 are configured as contactless shaft seals and the water level in the leakage water chamber K5 is held below the projections of seal w3 by means of a pump. A pump used for this purpose during normal operation, that is when the generator is running, is the pump 7. Pump 7 runs during normal operation and pumps the gap-leakage water flowing from the oxygen removal device 15 and ion exchanger A through a secondary branch I containing check valve r3 and magnetic valve V2 and into the suction chamber K2.

The magnetic valve V2 is controlled by a liquid level indicator 18 in the form of a sillometer probe such that the valve opens when the water level 19 is above an upper limit contact 18a of the liquid level indicator 18 and closes when the liquid level 19 in the collection vessel 13 drops below the lower limit contact 18b. Liquid level indicator 18 and magnetic valve V2 are connected via control leads not illustrated. The leakage water is drawn via the secondary branch l, from the collection vessel 13 so that, because of the lowest water level in the Ivessel '13, no air can be drawn in by means of the pump 7 which could lead to a stoppage of the conveying action. During the time that the turbogenerator l is inoperative or when the generator is coasting to a stop, there serves as a conveying device for drawing the leakage water from the chamber K5, a pump 16 which is rendered operative by means of a signal from the under-pressure monitor 20. With the coasting or stationary generator, because pump 7 no longer provides a sufficient pumping force, the underpressure in the suction chamberKZ falls off whereupon the under pressure monitor 20 actuates. Here also, to simplify the drawing, the signal leads are not shown. Due to action of the feedback pump 16, water will flow from the water storage means 11 via conduits l l to the chambers K3, K2 respectively; and water will also escape through the contactless seal into the chamber K5 and from there into the collection vessel 13 and over conduit 1, into the preparation vessel 15; this water flows via conduit 1 the valve channel 17a of the three-way magnetic valve V3 and the conduit 1, back into the water container 11.

Thus the liquid level 19 in vessel 13 reaches the lower limit contact 18b of the liquid level indicator 18 and this causes the magnetic valve V3 to be positioned by the latter so that the pump 16 conveys water back into the collection'vessel 13 over the valve path- 17b and conduit 1 until the liquid level 19 again reaches the upper limit level contact 18a. The liquid level indicator 18 serves thereby to also control the 3-way magnetic valve V3 when the feedback pump 16 is working. Once again, to simplify the drawing, the appropriate signal lines are not illustrated.

A blower 21 provided with an adjustable valve V4 is connected with chamber 5 and serves to evacuate the space within the latter. In this manner, air reaching the chamber K5 through the shaft seal W3 as well as the hydrogen portions reaching chamber K5 from the outlet chamber K3 via shaft seals w2 are evacuated to the ambient.

The cooling water circulation path illustrated in FIG. 1 is alsoconnected to a gas source for saturating the cooling water with hydrogen gas. In this connection, the water storage means 1 1 is used as an expansion ves sel which is arranged in the upper portion of the stator 2 over the level of the water connection head 9. The storage means 11 has a gas space 11b over the water space 11a having a water level 11a. The gas space thus defined constitutes a gas pressure cushion. For this purpose, a hydrogen gas source H communicates via gas input conduit 1 with the gas space 11b and a gas exhaust communicates with the gas space 11b via conduit I which is connected to the water storage means 11.

Hydrogen gas is supplied via conduit I and drawn away via conduit I such that a steady hydrogen stream is present in the gas space 11b. In this manner, the water conveyed through the water storage means 11 is brought into intimate contact with the hydrogen gas which goes continuously into solution so that the water is saturated with hydrogen gas.

Cooling water continuously saturated with hydrogen gas is pumped through conduit 1 into the suction chamber: during operation of the generator by means of pump 7, and during shutdown by rneans-ofthe feedback pump 16. During generator operation, this water saturated with hydrogen gas is forced by pump 7 into the inner circulation path portion 50 of the rotor cooling configuration via a second outer primary circulation path portion 10 and the inlet stub 8. The rotor cooling configuration comprises channel portions 6a, 5, 5a, 5b and 6b. A portion of the water exiting from the rotor and flowing back through conduit l to water storage means 11 can escape through the contactless shaft seal w2 to the chamber K5. This water contains a certain quantity of hydrogen gas which goes partially out of solution in chamber K5.

In addition, air is continuously drawn in from the ambient through the contactless shaft seal w3 and the oxygen 0 and the carbon dioxide CO contained therein must not reach the primary circulation path 50, 10, 10' so that undesired corrosion by the oxygen as well as an undesired increase in conductivity because of the CO is avoided. To remove the damaging oxygen from the leakage water which flows over from the leakage water chamber K to the collection container 13, there is provided the oxygen removal device 15 which has a palladium catalyst as a contact means 15a. With this palladium catalyst, the oxygen of the air-hydrogenwater mixture drawn from the chamber K5 and directed through device 15 is brought into reaction with the hydrogen contained in the water to yield water in accordance with the formula: 2H 0 2H O. To bind 1 liter of 0 2 liters of R are required or 1 gram of 0 is bound by 0.125 gram of H So that the above chemical reaction can be shifted to its safe side with respect to its equilibrium condition, there is a certain H surplus required and it is approximately 2.6 times the volume of the hydrogen, that is, a surplus of approximately 160 percent. Therefore, in the water flowing to the oxygen removal device 15 there must be maintained a hydrogen surplus relative to the oxygen content such that'the oxygen is converted almost completely to thereby hold the oxygen concentration in the water circulation path below an upper limit value. In addition, to maintain this limit value, the oxygen removal device 15 must have a sufficient specific load capacity.

The palladium catalyzer permits for example a specific load of approximately 50 m /h of water per cubic meter of palladium contact material and a filtration speed of approximately to 20 meters per hour. By means of a high quality contactless shaft seal w3, which if necessary can be provided with a water-ring stuffing-box seal, a hydrogen surplus of over 75 percent lying outside of the combustible gas concentration can be present. In this case, the leakage water directed to the oxygen removal device has the required hydrogen surplus relative to the oxygen volume.

On the other hand, the chamber can be operated with an air surplus so that the H portion remains under 3 percent in the gas space of chamber K5 wherewith corresponding quantities of air or hydrogen are dissolved into the leakage water. When the chamber is so operated the shaft seal W2 must be of especially high quality and, in this manner, only small amounts of leakage water and thereby small quantities of hydrogen reach the chamber K5 from chamber K3. The blower 21 forces the outside air drwan in through shaft seal w3 with a small hydrogen portion into the ambient. In this case, the leakage water or air-water-hydrogen mixture flowing to the oxygen removal device 15 does not have the required hydrogen surplus. To guarantee the required hydrogen surplus, an ancillary water conduit 1,, with adjustable valve V5 feeds into the conduit 1 going from the leakage water chamber K5 to the oxygen removal device 15. This conduit 1, is connected to the conduit 1 at location 22. Conduit I: comes from the water storage means 11 and therefore carries hydrogen saturated water.

The required additional water quantity can thereby be dependent from the hydrogen and oxygen content of the leakage water through the valve V5, so that the required hydrogen surplus is always available in the water streaming to the oxygen removal device 15. As

already mentioned, the oxygen removal device 15 can contain an anion exchanger in addition to the palladium-contact mass. In this situation, the ion exchanger A is simply a cation exchanger. If the oxygen removal device 15 simply contains a palladium catalyzer, it is preferable to configure the ion exhanger A as a combination anion-cation exchanger.

As indicated by the field of dashed lines 23, the chambers K1 to K3 are tilled with water during operation and shutdown, whereas chamber K5 is essentially a gas chamber into which leakage water quantities only enter through the shaft seal W2. The field of dashed lines 24 designate the water in collection vessel 13. The solid arrowheads in the outer circulation path portions 10, 10' and 50 indicate the normal flow direction of the water during operation. The outline arrows in the secondary circulation path 14 illustrate the direction of flow of the pumped leakage water during operation of the feedback pump 16.

The illustrated check valves rl to r3 prevent a flow of water against the indicated direction of flow. Nitrogen entering into the leakage water within the leakage water chamber K5 from the air in itself is not harmful to the cooling circulation path since it is an inert gas. The nitrogen, however, cannot collect in the cooling circulation path since it is displaced with the saturation of hydrogen gas within the water storage means 11 and is removed via conduit l together with the surplus cleaning hydrogen.

The shaft seal W1 is preferably also a contactless shaft seal so that the rotor 3 with its shaft end 3b can move axially without hinderance of the sealing action within the limits occurring as a practical matter. By

means of the throttle valve V1, an under-pressure or partial vacuum is adjusted in the suction chamber K2, for example, minus 0.3 atmospheres at a water temperature 40 C. such that this water temperature lies far below the boiling temperature corresponding to this steam pressure thereby precluding cavitation from occurring in the suction chamber K2 by occurring gas bubbles. There must also be maintained a certain minimum pressure with respect to the water temperature in the outlet chamber K3 so that no cavitation will occur. An expeditious value is for example 3 atmospheres water pressure by a water temperature of 60 C.

It is evident that the pump 7 pumps the cooling water drawn from the suction chamber K2 into the inlet chamber K1 in a direction opposite to the flow direction of the cooling water flowing in the central bore 6a of the shaft 6b. From the chamber Kl, pump 7 pumps the cooling water through the second outer circulation path portion 10' and the entrance inlet stub 8 into the central bore 6a. In this manner, a shaft seal can be saved or omitted between the suction chamber K2 and the inlet chamber K1 and there arise no sealing problems between the chambers K2 and K1 exhibiting a considerable pressure difference. Between the hollow shaft end 3b and the cooling water connection head 9 surrounding this shaft end and the pump wheel of the pump 7 as outer housing, the following are arranged ax; ially one after the other: the inlet chambers K1, the suction chamber K2, the outlet chamber K3 and the leakage water chamber K5. Between the chambers K2, K3, K5 are arranged respective separating walls W11,

w22, the latter having contactless shaft seals W1, W2 arranged thereon. In addition, the chamber K5 is sealed against the ambient by means of a radical separation wall W33 with shaft seal w3. The inlet chamber K1 and suction chamber K2 are separated from each other by a radial separating wall W00.

This construction of the water connection-head 9 is also followed in the embodiments according to FIGS. 2 to 4 although here improvements and refinements are provided in contrast to the embodiment according to FIG. 1. The parts corresponding to FIG. 1 are given the same reference characters in FIGS. 2 to 4. The water connection head 9 is schematically illustrated in FIG. 2 whereas in FIG. 3 more of the actual constructional details therefore are provided. FIG. 2 shows in combination with FIG. 3 that a pressure balancing chamber K4 filled with water is arranged between leakage water chamber K5 and the outlet chamber K3. Chamber K4 is connected with the water storage means 11 via the liquid conduit l with'check valve r5 and locking valve V7.

In this water storage means there is for example a gas pressure 1 p of 0.2 kplcm whereas a more favorable water pressure is present in the outlet chamber K3, namely, p,,,=3.5 kp/cm. The pressure balancing chamber K4 has a pressure level which lies between the pressure level of the outlet chamber K3 and the pressure level of the chamber K5 and in this way chamber K4 serves to step-wise reduce the pressure drop between chamber K3 and chamber K5.

Because the shaft gaps which lie between the chamber K4 on the one hand, and the chambers K5 or K3 on the other hand, are sealed with contactless shaft seals w4 and w2 respectively, the quantity of leakage water which-flows over from chamber K4 to chamber K5 is held relatively small. As the field of dashed-lines 23 in FIGS. 3 and 2 illustrate, the chambers Kl to K4 are filled with the cooling water of the rotor cooling circulation path.If there is a pressure of atmosphere in the leakage water chamber K5, the shaft seals w4 need only seal against a pressure difference of 0.2 atmosphere, the latter being taken with respect to the pressure in chamber K4 of p =+0.2 atmospheres.

The advantage of the pressure balancing chamber K4 is especially due to the fact that a normal contactless shaft seal as illustrated in section in FIG. 3a is adequate for all shaft seals wl to w3 as well as for the shaft seals w4, wA. In FIG. 3a reference numeral 25 designates the sealing'projections which are arranged at the inner periphery of thesealing shells 26 surrounding the shaft. The sealing sleeves 26 are each constructed of two halves with axial joining means to facilitate construction. The sealing projections 25 are shown in FIG. 3a in simplified illustration, actually, there are substantially more sealing strips provided per unit length. These sealing strips 25 are arranged with a gap s with respect to the outer periphery of the shaft 3b.

' A further refinement of the sealing according to FIGS. 2 and 3 is achieved by connecting a gas evacuation chamber K6 in front of the leakage-water chamber K5 in a direction toward the ambient, the chamber K6 having practically the same pressure level as the chamber K5 and being sealed with respect to the ambient by means of a contactless end seal wa.

tion, that is, the hydrogen portion of the total volume of the chamber K6 lies under 3 percent. In this way within the chamber K6 bordering on the ambient, no combustible gas concentration can occur, and in addition, no hydrogen can penetrate toward the ambient through the end shaft seal wa. Reference designation I designates a water emptying conduit with an emptying valve V8.

Chambers K4, K5, K6 which are disposed axially of outlet chamber K3 are separated from each other by radially extending partion walls WM and W33. The respective stationary portions of the shaft seals w4 and w3 are arranged at the inwardly directed periphery of the separating walls w44 and W33 respectively. The gas exhaust chamber K6 is separated with respect to the ambient by a separating wall wa which carries the shaft seal wa.

It is not required to prevent the formationof a combustable gas mixture within the leakage water chamber K5 since this chamber is connected ahead of the gas exhaust chamber K6 and further, because the walls of chamber K5 can be appropriately strengthened, so that as a practical operation the case of an ignition of a combustible gas mixture within the chamber K5 is without significance. It is however, also possible, as will be explained further below, to dimension or arrange the respective gas quantities in chamber K5 so that here also no combustible gas mixture can form; this can be performed by means of additional sealing measures or exhaust measures. In FIG. 3, the conduit stubs corresponding to conduits 1,, 1 1 1 I and 1, from FIG. 2 are designated with reference characters e1 to e3, e5, e6, and e7. Reference numeral 27 designates the support walls position normal to the rotor shaft axis and numeral 28 designates the supportingfeet of the water connection head 9. g

The return of the leakage water from the leakage water chamber K5 is achieved with the modified embodiment according to FIGS. 2, 2a an especially reliable way via the following: conduits I a cooler W3,

conduit I the two parallel connected branches I and 1, which are provided with respective feed-back pumps 160 equipped with control valves V9, V9 and check valve r6, the conduit 1 the conduit branch 1 with an oxygen removal device 15 and blocking valves V11, V12, the conduit branch L21 with ion exchanger or mixed-bed filter A and blocking valves V13 oi- V14, and finally, via conduit branch 1 with check valve r5 to the rotor water exit line conduit L4. The one branch I or I is a reserve branch which is normally only connected when a failure occurs in the parallel branch.

Reference character I I designate incoming and outgoing lines for the coolers W3 as well as W1, .W2. Switching for feeding back the prepared leakage water with feedback branch I and control-valve V is illustrated simplified with only one feedback'pump in FIG. 4. The feedback pump 160 has, in this embodiment, the task to'pump back the leakage water into the circulation path during operation of the generator as well as when the generator is not operating. The proper function of pump 160 is especially important as in the case of the switching arrangement according to FIG. 1, since failure of the pump could cause water to flow from the water storage means 11 via the water connection head 9 and its shaft seals into the machine hall where the turbogenerator is installed. For this reason, the reserve pump is provided, see FIGS. 2, 2a.

For a reliable operation of the pump 160, the following requirements must be fulfilled: The pump must neither be permitted to run dry because of the usual pump glide ring seals nor run in water because of heating; the pump should not be intermitently turned on and off and must pump back only so much fluid as is made available to it and not more, since otherwise, the pump will draw air, and the pump should not pump less fluid than is available since then, the chamber K5 will overrun.

The control of the pump is configured as self-regulating in order to avoid having to continuously switch the pump by means of an arrangement comprising water level indicators, three-way magnetic valves, etc. Referring to FIG. 4, the leakage water chamber K5 is connected ahead of the feedback pump 160 via downcomer conduit l the pump 160 being connected in series with water cooler W3. The pressure side of pump 160 is connected with a second flow resistance constituted by a control valve V90 to a down-comer conduit l via a first resistance in the form of a control valve V9 and a return conduit 1 On the other hand, the pressure side of pump 160 is connected via the first flow resistor V9, the oxygen removal device 1S,'the ion exchanger A and the check valve r5 by means of the conduit l to the conduit 1, of the primary circulation path 10. The difference in elevation of the pump 160 with reference to the rotor shaft 3b and thereby the length of the downcomer conduit I amounts to approximately Ml meters and corresponds to a pressure fall of approximately 1 atmosphere. With this height difference taken with reference to the shaft axis and a pressure in the water storage means 11 of 0.5 kp/cm there is a constant pressure of 1.5 kp/cm on the one side of the check valve r when the generator is operational and when the generator is not operational. If the pumping head of the pump 160 is adjusted to just below this value by means of the valves V9 and V90, the pump cannot pump against this pressure so long as the suction side or inlet pressure is close to zero which corresponds to a very low water level in the down-comer conduit 1 for example, as indicated by position 29. In this condition, the pump 160 operates in a defined circulation path operation which is adjustable by means of throttle valves V9, V90 adjustable so that the pumps pump less than their rated volume.

Should the water level in the down-comer conduit 1 for example, climb to the position 30 as a consequence of a continuous flow of leakage water, the inlet pressure increases accordingly and therewith also the pressure behind the pump 160. The back pressure of 1.5 kp/cm is exceeded and the pump conveys the leakage quantity back into the conduit 1., while a portion of the leakage water flows in the circulation path operation. In this circulation path, flowing water is held to the required low temperature by the cooler W3. Essential in this connection, is that the pump 160 in combination with the check valve r5 is self-regulating without ancillary measuring devices. By means of the pressure measuring instruments 1 to 3 and the pressure values next to these pressure instruments is indicated in which magnitude the value of the pressure occurring in practice may lie.

To complete the security system in connection with the feedback pumps 160 (see FIG. 2a), there is provided a safeguard against loss of both pumps 160 in the form of an overflow pipe 33 with a riser loop 33a connected to the down-comer conduit at a connection location 31 lying shortly below the leakage-water chamber K5. The pipe 33 feeds into the drain 32. The lower U-shaped extending end 33b of the overflow pipe 33 contains a sealing liquid column 34 in its U-portion 33b which constitutes in the normal case an air seal or trap. For the sealing liquid column 34, there is provided a corresponding sealing liquid inlet line 1 with blocking device 24a and inlet funnel 2412. In the event of a fault, that is, if the water level in the down-comer conduit I climbs over the upper end of the loop riser 3311, the water quantity entering the pipe 33 will press the sealing liquid column at 34 into the drain 32, so that no water will run into the machine hall from the leakage-water chamber K5.

In the conduit going from the chamber K5 to the oxygen removal device which in this embodiment is designated as conduit 1 an additional water conduit 1,, feeds into the latter. Conduit 1, is connected with the rotor water conduit 1 coming from the water storage 11 at location 35. By means of the valve V5 of the additional water line 1, the quantity of additional water saturated with hydrogen which is to be mixed with the leakage water, can be adjusted such that the required hydrogen surplus is always maintained in the leakage water quantity flowing to the oxygen removal device 15. In the embodiment according to FIG. 2, with a quantity of leakage water of approximately 1.4m per hr. a quantity of to 200 liters of hydrogen saturated additional water per hour would be added to the quantity of leakage water so that the required hydrogen surplus would be maintained. In this operation, the oxygen content behind the oxygen removal device amounted to 7 micrograms oxygen per liter and in the primary circulation path 10, 10, it amounted to approximately 9 micrograms of oxygen per liter. This oxygen content lies below the required highest value permissible in practice. By means of the measure of supplying the additional water, there is obtained the condition that one is not dependent upon the hydrogen gas portion in the leakage-water chamber K5 wherewith this gas portion corresponds to the portion dissolved in the leakage water and wherewith the required hydrogen surplus can always be maintained in the leakage water flowing to the oxygen removal device 15.

Even when the chambers K5 K6 are at the same pressure level, a change in the gas portion can occur with instantaneous lowering or instantaneous raising of the leakage water level in chamber K5, for example, when a portion of the mixuture is forced out of chamber K5 through shaft seal W3 with a rising level of the leakage water and, when this level again falls, a small quantity of air is drawn in by suction from chamber K6.

According to a further feature of the embodiment, the hydrogen portion. of the gas in the chamber K5 is brought to a zero value by means of an additional suction device Sa equipped with a suction conduit 1 and adjusting valve V4 and blower 21'. I-Ierewith, there is drawn by suction through shaft seal w3 facing the gas evacuation chamber K6 such a quantity of air that the hydrogen quantities leaving the leakage water are held below the combustion gas concentration by the air surplus, that is,'the hydrogen portion returns practically to zero. In this instance, additional quantities of hydrogen saturated additional .water tnust be supplied into the conduit 1,, via the ancillary water conduit 1, Practical values of the operation were an additional water quantity of approximately 1.7 m per hour with a leakage water quantity of approximately 1.4 m per hour. Such an operation can be carried out with conventional contactless shaft seals according to FIGS. 3, 3a. The air quantities entering into the chamber K5 and the hydrogen quantities can be held very small with an embodiment according to FIG. 2 where there is used a refined configuration of the contactless shaft seal W3, 1424 or wa as explained in connection with the switching arrangement of FIG. 1. For example, the referred to shaft seals can at least partially be configured as waterring stuffing box seals according to FIG. 3b.

In the simplified illustration of FIGf3b, reference designation 3b indicates a shaft section with a flange or shaft collars 35, 36. On the shaft section 3b, the impeller 37 is secured with blades 37a wherewith impeller 37 with shaft section 3b rotates while maintaining a radial gap S with respect to the. ring surface 38a of the sealingpocket 38. The sealing pocket 38 is stationary with respect to the housing and is configured in the form of a circular channel wherein a centrifugal force dependent water ring 39 is pressed against the ring surface 38a. The water ring 39 presses against the side with the low pressure P2 of the water ring portion 39a and presses on the side with the higher-pressure P1 of the water ring portion 39b. The radial heights of the water "ring portions 39b to 39a adjust in correspondence't'o the pressure proportion P1/P2.

In order that the housing portion 40 having the ring pocket 30a can tolerate axial movements of the shaft, this housing portion 40 is arranged so as to be displaceable in the axial direction and is coupled to be axially displaceable with the shaft collars 35, 36 and the shaft section 36' by means of an intermediate connection of the roller bearing rings 41, 42. The contrast thereto, the ring pocket carrier 40 is arranged so as to be non-displaceable in the peripheral direction. Such a a water ring stuffing box seal according to FIG. 3b functions properly only when the shaft is turning, whereas when theshaft-is stationary, the conventional contactless shaft seals according to FIGS. 3, 3a take over the sealing function. f

In the embodiment according to FIGS. 2, 3, a throttle valve V6 with a check valve r1 is arranged in the outlet chamber. conduit1 In this instance, the overpressure p in the outlet chamber K3 measured with respect to the overpressure P of the hydrogen gas present in the water, storage or measured with respect to the pressure in the pressure-balancing chamber K4 can be adjusted to such a minimum value that, under all circumstances, cavitation in the outlet bores of the shaft will be prevented. According to an empirically determined approximation function, the minimum value if preferably 'af b'j' -d V P A favorablepressure value paidfor practical operation is for example P, 3.5 kp per cm at P 0.2 kp/cm. In this manner, a de-gassing of the water in the region of the outlet bore 6c is practically completely prevented.

The water storage illustrated more precisely in FIG. 2 is essentially a U-shaped vessel whose one arm 110 is directed to the rotor outlet water via conduit l and from whose other arm 111 the hydrogen saturated water is conducted away via conduit 1 In a direction opposite to this water flow, the hydrogen flow gas is directed via conduit 1 to the arm 111 and, after flowing through the gas space 11b, is directed away via conduit 1,, at the end of the arm 110. In this connection, compare arrow 1 12 for the water flow to the arrow 113 for the hydrogen flow. Because of this advantageous opposite flow, only small quantities of hydrogen flow gas are necessary and, with a practical operation, only approximately 100 liters per hour of hydrogen are required. I

The stator cooling system 43 is connected to the primary circulation path 10, 10' via conduits I I I I and 1 The stator cooling system 43 is not explained in detail in the following since its understanding is not required for an understanding of the invention. The following however is mentioned: between the primary inlet conduit 1 which is joined with conduit 1 at location 44 and the water storage means 11, there is located a branch 43a for supplying the cooling channels of the stator winding bars, a branch 43b for pressure plate cooling the left portion of. theend machine, a branch 43c for pressure plate cooling the right machine end as well as a branch 43d for cooling the passage 45 and ring conductors 46. Reference designation 43a1 designates an input collection ring chamber and 43a2 an outlet ring collection chamber for the water cooling of the stator winding rods. The flow quantities of cooling water for the above-mentioned branches are adjusted with the valves V15, V16, V17 and V18.

A division of the entire quantity of cooling water flowing through conduit 1 is possible at branch point 44 with valve V19 in the rotor water inlet conduit 1 such that a portion flows through a conduit 1 to the stator cooling system 43 and another portion flows to the cooling channels of rotor 3. In combination with the fact that the inner region of generator 1 is provided with a hydrogen gas filling, as is conventional it is especially advantageous that the cooling water is saturated with hydrogen. The hydrogen gas filling, even when exhibiting an overpressure relative to the ambient atmosphere, can cause only small ventilation losses with a running rotor 3 becauseof its low density. Hydrogen gas which diffuses through the stator water inlet and outlet hoses thereby reaches the water cooling circulation path so that the cooling circulation path does not become contaminated; these hoses are made of Teflon and serve as an isolating distance. a

The parallel connected cooling or heat exchanger W1, W2 are normally both in operation and are so arranged that for emergency operation, when only one is connected, the one connected can take over approximately to percent of the rated cooling. The oxygen removal device 15 with palladium catalyzer is in combination with the contactless shaft seals of the illustrated water connection head 9 especially advantageous since, in this way, a safe and reliable operation without an expensive sealing system is possible.

Turbogenerators or electric machines which are already installed and which are equipped with contacted or worn shaft seals together with rotor water inlet and the rotor water outlet locations can be equipped with such an oxygen removal device advantageously as an additional safety member built into the preparation and return cooling assembly for the situation where air penetrates into the leakage water circulation path by means of a failure of the tightness of a shaft seal wherewith it is additionally necessary to mix hydrogen saturated additional water in the required quantities with oxygen enriched leakage water. In this manner, there is obtained in a simple manner, a prevention of undesired corrosion in the rotor and stator water circulation paths without making it necessary to immediately shut down the turbogenerator or the electrical machine.

To those skilled in the art it will be obvious upon a study of this disclosure that cooling apparatus according to my invention may be modified in various respects and. may be given designs other than illustrated and described herein, without departing from the essential features of my invention and within the scope of the claims annexed hereto.

I claim:

1. Apparatus for supplying cooling water to the cooling channels of an electrical machine rotor having a rotor shaft, comprising an inlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, an outlet chamber communicating with the rotor channels for receiving the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels, said outlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, primary conveying means connected between said outlet 7 chamber and said inlet chamber for conducting the water between said outlet chamber and said inlet chamber; pump means for supplying the cooling water to said inlet chamber under pressure and for urging the same through said primary conveying means; a leakage water chamber next to said outlet chamber in a direction toward the ambient, said leakage water chamber having a first contactless seal disposed with respect to the shaft where said leakage chamber adjoins the ambient'and a second contactless seal where said leakage chamber adjoins said outlet chamber, said leakage chamber serving to collect cooling water which leaks through said second seal during normal operation, said cooling water being mixed with air leaking into said leakage-water chamber from the ambient, said pump means communicating with said leakage-water chamber for drawing the leakage cooling water from said leakage chamber, hydrogen gas supply means connected to said conveyingmeans for saturating the cooling water conveyed by the latter with hydrogen, and an oxygen removal device for receiving the leakage water mixed with air, said device being connected between said leakage water chamber and said primary conveying means.

2. Apparatus according to claim 1, said pump means comprising a shaft pump mounted on one end portion of the rotor shaft so as to be rotatable therewith and said apparatus further comprising a stationary cooling water connection head surrounding said end portion of the shaft, said inlet chamber and said outlet chamber both constituting respective portions of said connec tion head, said rotor shaft having a central bore and an annular bore concentric with the latter, said central bore and said annular bore constituting respective portions of said primary conveying means, said connection head including a suction chamber connected ahead of said inlet chamber, said shaft pump being arranged with respect to said primary conveying means for pumping the cooling water from said suction chamber into said inlet chamber and then into said central bore, the cooling water flowing through said central bore in a direction opposite to the direction that the cooling water is pumped by said shaft pump; said connection head being arranged as an outer housing surrounding said end portion and said shaft pump; said inlet chamber, said suction chamber and said outlet chamber being within said housing and being arranged axially along said end portion one next to the other in the last recited order when viewed from the end of the shaft; a first separating wall disposed between said suction chamber and said outlet chamber, a first contactless shaft seal mounted on said separating wall, said leakage-water chamber being arranged within said housing after said outlet chamber in axial direction along said end portion, a second separating wall disposed between said outlet chamber and said leakage-water chamber, and a second contactless shaft seal mounted on said second separating wall.

3. Apparatus according to claim 2, said primary conveying means comprising a flow path between said inlet chamber and said central bore, the latter communicating with the cooling channels of the rotor for directing the cooling water thereto, a stationary entrance stub located at the inlet of said central bore, a branch path connected into said flow path, a filter and a cooler connected into said branch path and loading the pressure side of said shaft pump, the output of said branch path being connected into said entrance stub, said entrance stub extending from the ambient through said inlet chamber in seal-tight relation to the latter.

4. Apparatus according to claim 1, each of said contactless shaft seals being configured as a labyrinth seal comprising a stationary part, and a rotating part separated from said stationary part by a radial distance of sufficient size to prevent rubbing therebetween which would otherwise occur because of radial and axial movements of the rotor.

5. Apparatus according to claim 4, one of said parts overlapping the other of said parts, said parts being axially displaced a sufficient distance to prevent rubbing therebetween which would otherwise occur because of outlet chamber communicating with the rotor channels for receiving the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels, said outlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, primary conveying means connected between said outlet chamber and said inlet chamber for conducting the water between said outlet chamber and said inlet chamber; pump means for supplying the cooling water to said inlet chamber under pressure and for urging the same through said primary conveying means; a leakage water chamber next to said outlet chamber in a direction toward the ambient, said leakage water chamber having a first contactless seal disposed with respect to the shaft where said leakage chamber adjoins the ambient and a second contactless seal where said leakage chamber adjoins said outlet chamber, said leakage chamber serving to collect cooling water which leaks through said second seal during normal operation, said cooling water being mixed with air leaking into said leakage' water chamber from the ambient, said pump means communicating withsaid leakage-water chamber for drawing the leakage cooling water from said leakage chamber, hydrogen gas supply means connected to said conveying means for saturating the cooling water conveyed by the latterwith hydrogen, and an oxygen removal device for receiving the leakage water mixed with air, said oxygen removal device being connected between said leakage water chamber and said primary conveying means and having a palladium catalyzer which serves as a contact medium for causing a chemical reaction whereby the hydrogen and oxygen of the air combine to form water.

8. An apparatus according to claim 7, control means connected in proximity with said hydrogen gas supply means and said oxygen removal device for maintaining a hydrogen surplus relative to the oxygen content in the water flowing to said oxygen removal device so as to keep the oxygen content flowing in said primary conveying means below an upper limit value.

9. An apparatus according to claim 8, said hydrogen gas supply means comprising a water storage configured as an expansion tank, and when containing water, said tank defining a gas space between its wall and the surface of the water contained therein, said gas space being a gas pressure cushion when filled with gas, gas inlet means and gas outlet means communicating with said gas space at respective locations in the wall of said tank for supplying hydrogen gas flowing in' a continuous stream through said gas space whereby the water becomes saturated with hydrogen gas.

10. An apparatus according to claim 9, a first conduit connecting said leakage-water'chamber and said oxygen removal-device, an ancillary conduit feeding into said first conduit from said water storage for supplying hydrogen saturated water to said oxygen removal device, said control means being disposed in said ancillary conduit for adjusting the flow of hydrogen saturated water to said oxygen removal device in accordance with the hydrogen surplus required for said chemical reaction in view of the composition of the leakage-water flowing from said leakage-water chamber.

11. An apparatus according to claim 9, comprising a rotor-water conduit connected between said outlet chamber and said water storage, a throttle valve arranged on said rotor-water conduit for adjusting the pressure P in said outlet chamber to prevent the occurrence of cavitation in the latter, said pressure P being taken with reference to the overpressure P of the hydrogen gas in said water storage and being adjustable to a minimal value given by li hfi empirically derived approximation formula: P 6 3 P 12. An apparatus according to claim 11, said minimal pressure obtained with said formula being 3.5

, kp/cm when P =0.2 kg/cm 13. Apparatus according to claim 10, comprising gas exhaust means connected to said leakage-water chamber for drawing air through said first contactless seal into said leakage-water chamber in an amount sufficient to hold the hydrogen escaping from the leakage water to a concentration below the combustion concentration, and said control means being dimensioned to adjust the flow of hydrogen saturated water through said ancillary conduit in sufficient quantity to accommodate the increased oxygen concentration in the leakage water resulting from thepresence of the air drawn by said gas exhaust means.

14. Apparatus according to claim 9, comprising a pressure-balancing chamber disposed between said outlet chamber and said leakage-water chamber, said pressure-balancing chamber defining respective interfaces with saidleakage-water chamber and said outlet chamber and being fillable with cooling water at a pressure level lying between the pressure level of said outlet chamber and said leakage-water chamber, said interfaces having respective shaft-gaps, and a contactless shaft seal disposed at each of said shaft-gaps for sealing the latter.

15. Apparatus according to claim 14, comprising a gas evacuation chamber connected in front of said leakage-water chamber in the direction toward the ambient, the pressure level obtaining in said gas evacuation chamber being substantially the same as the pressure level in said leakage-water chamber, said gas evacuation chamber having an intermediate shaft seal between the same and said leakage-water chamber and having an end shaft seal for sealing the latter relative to the ambient, gas exhaust means connecting said gas evacuation chamber with the ambient for exhausting air from said evacuation chamber through said end shaft seal in such quantities that the hydrogen reaching the gas evacuation chamber from said leakage-water chamber through said intermediate shaft seal lies below the combustible gas concentration.

16. Apparatus according'to claim 15, said intermediate shaft seal being configured at least partially as a water ring s tuffing box seal.

17. Apparatus according to claim 15, said outlet chamber, said pressure-balancing chamber, said leakage-water chamber and said gas evacuation chamber being arranged axially one next to the other, and respective separating walls intermediate each two mutually adjacent ones of said axially arranged chambers, said separating walls having respective inner peripheries in surrounding relation to the rotor shaft, the respective seals at said inner peripheries having respective stationary parts said stationary parts being secured to said inner peripheries respectively.

18. Apparatus according to claim l4, wherein the region occupied by the water in said water storage defines a water space, said pressure-balancing chamber being connected to said water storage via a pressurebalancing conduit feeding into said water space.

19. Apparatus for supplying cooling water to the cooling channels of an electrical machine rotor having a rotor shaft, comprising an inlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, an outlet chamber communicating with the rotor channels for receiving the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels, said outlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, primary conveying means connected between said outlet chamber and said inlet chamber for conducting the water between said outlet chamber and said inlet chamber; pump means for supplying the cooling water to said inlet chamber under pressure and for urging the same through said primary conveying means; a leakage water chamber next to .said outlet chamber in a direction toward the ambient, said leakage water chamber having a first contactless seal disposed with respect to the shaft where said leakage chamber adjoins the ambient and a second contactless seal where said leakage chamber adjoins said outlet chamber, said leakage chamber serving to collect cooling water which leaks through said second seal during normal operation, said cooling water being mixed with air leaking into said leakage-water chamber from the ambient, said pump means communicating with said leakage-water chamber for drawing the leakage cooling water from said leakage chamber, hydrogen gas supply means connected to said conveying means for saturating the cooling water conveyed by the latter with hydrogen, and an oxygen removal device for receiving the leakage water mixed with air, said device being connected between said leakage water chamber and said primary conveying means, a self-regulating feed-back pump, a water cooler connected to said feed-back pump, a downcomer conduit for connecting said feed-back pump after said leakage-water chamber, the pressure side of said feed-back pump being connected via a first flow resistance, on the one hand, to said down-comer line via a return conduit having a second flow resistance, on

the other hand, to said primary conveying means via a forwarding conduit having a check valve, said oxygen removal device being connected into said forwarding conduit, said feedback pump having a back pressure referred to said check valve above the pressure drop produced by said feedback pump reduced by the pressure loss occurring up to said check valve, said feedback pump having an inlet pressure dependent upon the level of the water in said down-comer conduit, said feedback pump having a delivery head being controllable by said inlet pressure such that said feedback pump pumps only in a circulating path comprising said cooler and said return conduit when said water level is below a minimum height, whereas said feedback pump pumps an amount of cooling water into said primary conveying means when said inlet pressure exceeds said back pressure in response to an increase of said water level over said minimum height, said amount of cooling water corresponding to the pressure excess of said inlet pressure over said back ressure.

20. Apparatus accor ing to claim 19, said first flow resistance and said second flow resistance each being an adjustable control valve.

21. Apparatus according to claim 19, said hydrogen gas supply means comprising a water storage, and said primary conveying means comprising a rotor-water conduit connected between said outlet chamber and said water storage, said forwarding conduit being connected to said rotor-water conduit.

22. Apparatus according to claim 19, comprising a second feedback pump connected in parallel with said first mentioned feedback pump as a reserve pump, and an overflow assembly comprising a drain, an overflow pipe having a riser loop and emptying into said drain whereby said apparatus is protected against flooding should both of said feedback pumps fail, said overflow pipe having a U-shaped end portion and being connected to said down-comer conduit at a location below said leakage-water chamber, and sealing liquid column means arranged in said U-shaped end portion for sealing said overflow pipe under the non-failure condition of said feedback pumps, said column means being responsive to pressure occurring in the event of failure of both of said pumps such that said column means empties into said drain. 

1. Apparatus for supplying cooling water to the cooling channels of an electrical machine rotor having a rotor shaft, comprising an inlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, an outlet chamber communicating with the rotor channels for receiving the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels, said outlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, primary conveying means connected between said outlet chamber and said inlet chamber for conducting the water between said outlet chamber and said inlet chamber; pump means for supplying the cooling water to said inlet chamber under pressure and for urging the same through said primary conveying means; a leakage water chamber next to said outlet chamber in a direction toward the ambient, said leakage water chamber having a first contactless seal disposed with respect to the shaft where said leakage chamber adjoins the ambient and a second contactless seal where said leakage chamber adjoins said outlet chamber, said leakage chamber serving to collect cooling water which leaks through said second seal during normal operation, said cooling water being mixed with air leaking into said leakage-water chamber from the ambient, said pump means communicating with said leakage-water chamber for drawing the leakage cooling water from said leakage chamber, hydrogen gas supply means connected to said conveying means for saturating the cooling water conveyed by the latter with hydrogen, and an oxygen removal device for receiving the leakage water mixed with air, said device being connected between said leakage water chamber and said primary conveying means.
 2. Apparatus according to claim 1, said pump means comprising a shaft pump mounted on one end portion of the rotor shaft so as to be rotatable therewith and said apparatus further comprising a stationary cooling water connection head surrounding said end portion of the shaft, said inlet chamber and said outlet chamber both constituting respective portions of said connection head, said rotor shaft having a central bore and an annular bore concentric with the latter, said central bore and said annular bore constituting respective portions of said primary conveying means, said connection head including a suction chamber connected ahead of said inlet chamber, said shaft pump being arranged with respect to said primary conveying means for pumping the cooling water from said suction chamber into said inlet chamber and then into said central bore, the cooling water flowing through said central bore in a direction opposite to the direction that the cooling water is pumped by said shaft pump; said connection head being arranged as an outer housing surrounding said end portion and said shaft pump; said inlet chamber, said suction chamber and said outlet chamber being within said housing and being arranged axially along said end portion one next to the other in the last recited order when viewed from the end of the shaft; a first separating wall disposed between said suction chamber and said outlet chamber, a first contactless shaft seal mounted on said separating wall, said leakage-water chamber being arranged within said housing after said outlet chamber in axial direction along said end portion, a second separating wall disposed between said outlet chamber and said leakage-water chamber, and a second contactless shaft seal mounted on said second separating wall.
 3. Apparatus accOrding to claim 2, said primary conveying means comprising a flow path between said inlet chamber and said central bore, the latter communicating with the cooling channels of the rotor for directing the cooling water thereto, a stationary entrance stub located at the inlet of said central bore, a branch path connected into said flow path, a filter and a cooler connected into said branch path and loading the pressure side of said shaft pump, the output of said branch path being connected into said entrance stub, said entrance stub extending from the ambient through said inlet chamber in seal-tight relation to the latter.
 4. Apparatus according to claim 1, each of said contactless shaft seals being configured as a labyrinth seal comprising a stationary part, and a rotating part separated from said stationary part by a radial distance of sufficient size to prevent rubbing therebetween which would otherwise occur because of radial and axial movements of the rotor.
 5. Apparatus according to claim 4, one of said parts overlapping the other of said parts, said parts being axially displaced a sufficient distance to prevent rubbing therebetween which would otherwise occur because of radial and axial movements of the rotor.
 6. Apparatus according to claim 1, comprising contact-making shaft seals for sealing said primary conveying means from the ambient to protect the rotor channels from the oxygen of air penetrating to the latter in the event of a fault.
 7. Apparatus for supplying cooling water to the cooling channels of an electrical machine rotor having a rotor shaft, comprising an inlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, an outlet chamber communicating with the rotor channels for receiving the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels, said outlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, primary conveying means connected between said outlet chamber and said inlet chamber for conducting the water between said outlet chamber and said inlet chamber; pump means for supplying the cooling water to said inlet chamber under pressure and for urging the same through said primary conveying means; a leakage water chamber next to said outlet chamber in a direction toward the ambient, said leakage water chamber having a first contactless seal disposed with respect to the shaft where said leakage chamber adjoins the ambient and a second contactless seal where said leakage chamber adjoins said outlet chamber, said leakage chamber serving to collect cooling water which leaks through said second seal during normal operation, said cooling water being mixed with air leaking into said leakage-water chamber from the ambient, said pump means communicating with said leakage-water chamber for drawing the leakage cooling water from said leakage chamber, hydrogen gas supply means connected to said conveying means for saturating the cooling water conveyed by the latter with hydrogen, and an oxygen removal device for receiving the leakage water mixed with air, said oxygen removal device being connected between said leakage water chamber and said primary conveying means and having a palladium catalyzer which serves as a contact medium for causing a chemical reaction whereby the hydrogen and oxygen of the air combine to form water.
 8. An apparatus according to claim 7, control means connected in proximity with said hydrogen gas supply means and said oxygen removal device for maintaining a hydrogen surplus relative to the oxygen content in the water flowing to said oxygen removal device so as to keep the oxygen content flowing in said primary conveying means below an upper limit value.
 9. An apparatus according to claim 8, said hydrogen gas supply means comprising a water storage configured as an expansion tank, and when containing water, said tank defining a gas space between its wall and the surface of the water contained therein, said gas space being a gAs pressure cushion when filled with gas, gas inlet means and gas outlet means communicating with said gas space at respective locations in the wall of said tank for supplying hydrogen gas flowing in a continuous stream through said gas space whereby the water becomes saturated with hydrogen gas.
 10. An apparatus according to claim 9, a first conduit connecting said leakage-water chamber and said oxygen removal device, an ancillary conduit feeding into said first conduit from said water storage for supplying hydrogen saturated water to said oxygen removal device, said control means being disposed in said ancillary conduit for adjusting the flow of hydrogen saturated water to said oxygen removal device in accordance with the hydrogen surplus required for said chemical reaction in view of the composition of the leakage-water flowing from said leakage-water chamber.
 11. An apparatus according to claim 9, comprising a rotor-water conduit connected between said outlet chamber and said water storage, a throttle valve arranged on said rotor-water conduit for adjusting the pressure PIII in said outlet chamber to prevent the occurrence of cavitation in the latter, said pressure PIII being taken with reference to the overpressure PG of the hydrogen gas in said water storage and being adjustable to a minimal value given by the empirically derived approximation formula: PIII about
 6. Cube Root PG
 12. An apparatus according to claim 11, said minimal pressure obtained with said formula being 3.5 kp/cm2 when PG 0.2 kg/cm2.
 13. Apparatus according to claim 10, comprising gas exhaust means connected to said leakage-water chamber for drawing air through said first contactless seal into said leakage-water chamber in an amount sufficient to hold the hydrogen escaping from the leakage water to a concentration below the combustion concentration, and said control means being dimensioned to adjust the flow of hydrogen saturated water through said ancillary conduit in sufficient quantity to accommodate the increased oxygen concentration in the leakage water resulting from the presence of the air drawn by said gas exhaust means.
 14. Apparatus according to claim 9, comprising a pressure-balancing chamber disposed between said outlet chamber and said leakage-water chamber, said pressure-balancing chamber defining respective interfaces with said leakage-water chamber and said outlet chamber and being fillable with cooling water at a pressure level lying between the pressure level of said outlet chamber and said leakage-water chamber, said interfaces having respective shaft-gaps, and a contactless shaft seal disposed at each of said shaft-gaps for sealing the latter.
 15. Apparatus according to claim 14, comprising a gas evacuation chamber connected in front of said leakage-water chamber in the direction toward the ambient, the pressure level obtaining in said gas evacuation chamber being substantially the same as the pressure level in said leakage-water chamber, said gas evacuation chamber having an intermediate shaft seal between the same and said leakage-water chamber and having an end shaft seal for sealing the latter relative to the ambient, gas exhaust means connecting said gas evacuation chamber with the ambient for exhausting air from said evacuation chamber through said end shaft seal in such quantities that the hydrogen reaching the gas evacuation chamber from said leakage-water chamber through said intermediate shaft seal lies below the combustible gas concentration.
 16. Apparatus according to claim 15, said intermediate shaft seal being configured at least partially as a water ring stuffing box seal.
 17. Apparatus according to claim 15, said outlet chamber, said pressure-balancing chamber, said leakage-water chamber and said gas evacuation chamber being arranged axially one next to the other, and respective separating walls intermediate each two mutually adjacent ones of said axially arrAnged chambers, said separating walls having respective inner peripheries in surrounding relation to the rotor shaft, the respective seals at said inner peripheries having respective stationary parts said stationary parts being secured to said inner peripheries respectively.
 18. Apparatus according to claim 14, wherein the region occupied by the water in said water storage defines a water space, said pressure-balancing chamber being connected to said water storage via a pressure-balancing conduit feeding into said water space.
 19. Apparatus for supplying cooling water to the cooling channels of an electrical machine rotor having a rotor shaft, comprising an inlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, an outlet chamber communicating with the rotor channels for receiving the cooling water, the latter being heated and reduced in pressure by its passage through the rotor channels, said outlet chamber surrounding the rotor shaft in liquid-tight relation to the ambient, primary conveying means connected between said outlet chamber and said inlet chamber for conducting the water between said outlet chamber and said inlet chamber; pump means for supplying the cooling water to said inlet chamber under pressure and for urging the same through said primary conveying means; a leakage water chamber next to said outlet chamber in a direction toward the ambient, said leakage water chamber having a first contactless seal disposed with respect to the shaft where said leakage chamber adjoins the ambient and a second contactless seal where said leakage chamber adjoins said outlet chamber, said leakage chamber serving to collect cooling water which leaks through said second seal during normal operation, said cooling water being mixed with air leaking into said leakage-water chamber from the ambient, said pump means communicating with said leakage-water chamber for drawing the leakage cooling water from said leakage chamber, hydrogen gas supply means connected to said conveying means for saturating the cooling water conveyed by the latter with hydrogen, and an oxygen removal device for receiving the leakage water mixed with air, said device being connected between said leakage water chamber and said primary conveying means, a self-regulating feed-back pump, a water cooler connected to said feed-back pump, a down-comer conduit for connecting said feed-back pump after said leakage-water chamber, the pressure side of said feed-back pump being connected via a first flow resistance, on the one hand, to said down-comer line via a return conduit having a second flow resistance, on the other hand, to said primary conveying means via a forwarding conduit having a check valve, said oxygen removal device being connected into said forwarding conduit, said feedback pump having a back pressure referred to said check valve above the pressure drop produced by said feedback pump reduced by the pressure loss occurring up to said check valve, said feedback pump having an inlet pressure dependent upon the level of the water in said down-comer conduit, said feedback pump having a delivery head being controllable by said inlet pressure such that said feedback pump pumps only in a circulating path comprising said cooler and said return conduit when said water level is below a minimum height, whereas said feedback pump pumps an amount of cooling water into said primary conveying means when said inlet pressure exceeds said back pressure in response to an increase of said water level over said minimum height, said amount of cooling water corresponding to the pressure excess of said inlet pressure over said back pressure.
 20. Apparatus according to claim 19, said first flow resistance and said second flow resistance each being an adjustable control valve.
 21. Apparatus according to claim 19, said hydrogen gas supply means comprising a water storage, and said primary conveying means comprising a rotor-water conduit connected between said outlet chamber and said water storaGe, said forwarding conduit being connected to said rotor-water conduit.
 22. Apparatus according to claim 19, comprising a second feedback pump connected in parallel with said first mentioned feedback pump as a reserve pump, and an overflow assembly comprising a drain, an overflow pipe having a riser loop and emptying into said drain whereby said apparatus is protected against flooding should both of said feedback pumps fail, said overflow pipe having a U-shaped end portion and being connected to said down-comer conduit at a location below said leakage-water chamber, and sealing liquid column means arranged in said U-shaped end portion for sealing said overflow pipe under the non-failure condition of said feedback pumps, said column means being responsive to pressure occurring in the event of failure of both of said pumps such that said column means empties into said drain. 